经常有人问这个问题，其实官方枪支安全手册有基本原则，大家仔细读读，体会一下。

在自卫时使用致命武力

自卫时使用致命武力是否是正当的问题不能被归咎于有几个简单因素的列表。 这一章是以涉及自卫行为的刑事案件中通常提供给陪审团的说明为基础的，说明关于在自卫时使用致命武力的一般规则。

在保护生命和身体时允许使用的致命武力

当必须用来反抗威胁生命的暴力犯罪企图时， 一个人被其他人杀害可能证明为正当的， 如果处在相同、或者类似情况的理性人士认为出现以下情形时，  

(a) 被杀害的人企图犯下一项暴力以及威胁生命的犯罪；

(b) 这样的、正在被实施的犯罪具有迫在眉睫的危险；以及 

(c) 被迫采取行动的人士相信需要采取这样的武力以便从死亡、或者一项暴力以及威胁生命的犯罪中拯救他自己、或者她自己、或者其他人。 谋杀、故意伤害罪、强奸、以及抢劫是暴力和威胁生命犯罪的例子。 (Pen. Code, § 197.)

在自卫时使用致命武力的限制

当攻击者没有产生进一步的威胁时，自卫权终止。因此，最初被攻击的人有权自卫。 当自卫行为让攻击者不能造成进一步伤害时，自卫权的合法性就会终止，不能使用进一步的武力。 并且，一个人可以使用武力的程度应该是当处于相同、或者类似情况的一位理性人士认为防范即将来临的伤害时适度的，最大程度为致命武力。要注意使用过度的武力反击攻击可能导致民事、或者刑事惩罚，这一点是很重要的。

当一个人攻击其他人时，这个人最初没有自卫权。 然而，如果这样的人士试图停止进一步的搏斗、并且明确的把他或者她希望和平的想法通知对手，但是对手仍然继续搏斗，这样的情况这个人就重获自卫权，这样获得的自卫权和其他任何正在被攻击的人士所有的自卫权一样。

THE USE OF LETHAL FORCE IN SELF-DEFENSE

The question of whether use of lethal force is justified in self-defense cannot be reduced to a simple list of factors. This section is based on the instructions generally given to the jury in a criminal case where self-defense is claimed and illustrates the general rules regarding the use of lethal force in self-defense.

Permissible Use of Lethal Force in Defense of Life and Body

The killing of one person by another may be justifiable when necessary to resist the attempt to commit a forcible and life-threatening crime, provided that a reasonable person in the same or similar situation would believe that (a) the person killed intended to commit a forcible and life-threatening crime; (b) there was imminent danger of such crime being accomplished; and (c) the person acted under the belief that such force was necessary to save himself or herself or another from death or a forcible and life - threatening crime. Murder, mayhem, rape and robbery are examples of forcible and life - threatening crimes. (Pen. Code, § 197.)

Limitations on the Use of Force in Self-Defense

The right of self-defense ceases when there is no further danger from an assailant. Thus, where a person attacked under circumstances initially justifying self-defense renders the attacker incapable of inflicting further injuries, the law of self-defense ceases and no further force may be used. Furthermore, a person may only use the amount of force, up to deadly force, as a reasonable person in the same or similar circumstances would believe necessary to prevent imminent injury. It is important to note the use of excessive force to counter an assault may result in civil or criminal penalties.

The right of self-defense is not initially available to a person who assaults another. However, if such a person attempts to stop further combat and clearly informs the adversary of his or her desire for peace but the opponent nevertheless continues the fight, the right of self-defense returns and is the same as the right of any other person being assaulted.